Highlight alert

HTML

<div class="xforms-alert">
Invalid value
</div>

CSS

.xforms-alert {
  font-family: sans-serif;
  font-size: 14px;
  color: white;
  position: relative;
  width: 400px;
  padding: 7px;
  background: #b94a48;
  border: #b94a48 solid 1px;
  border-radius: 5px;
  margin-top: 20px;
}

.xforms-alert:before {
  content: "";
  position: absolute;
  left: 10%;
  top: -10px;
  border-style: solid;
  border-width: 0 10px 10px 10px;
  border-color: #b94a48 transparent;
  display: block;
  width: 0;
  margin: 0 0 0 -26px;
}